Load Transfer Platform on Saturated Soil Saves Costs

Neoloy® Geocells provided load transfer platform on saturated silty sand, for heavy port platform, Manizillo, Mexico

Challenge

A new 150,000 square meter multiple use terminal (MUT) was planned for Manzanillo port to handle 2.5 million tons of general purpose cargo and bulk minerals per year. The contractor was to build five 10,000 sq m platforms within a year with environmental friendly operating equipment and infrastructure. Construction was to be according to the highest international standards with a goal to exceed the planned handling capacity.

The only problem was the extreme site conditions for the terminal platform. The soil was saturated silty sand with a CBR <2%. Bulk handling of lead and zinc minerals, piled into mountains of ore on the dock could reach loads of 35 ton/m2. The terminal foundation was constructed on vertical columns; therefore the reinforcement solution had to function as a load transfer platform as well.

Due to the extreme site conditions and project requirements, Innovator and Ancora Engineering worked together with PRS to develop a reliable design for a geocell reinforced load transfer platform (LTP).

Conventional Solution

Load transfer platforms of concrete, hydraulic-bonded or composite geosynthetic (geogrid) layers were too expensive or insufficient. The thickness of an unreinforced solution would have been much thicker and costly.

Neoloy Geocell Solution

Neoloy Geocells were chosen for their excellent load distribution mechanism. Neoloy reinforcement acts as a stiff mattress, distributing vertical loads widely and reducing settlements. This effectively transfers applied loads directly to vertical columns.

First a 5 cm working platform of lightweight concrete was poured to create a stable working foundation, after subgrade excavation and capping.

Two layers of Neoloy 330-120 (120 mm height) with 12 cm of 1” gravel fill were installed directly over the working platform and compacted with an extra 3 cm overfill over each layer. A layer of 115 cm controlled subgrade undercut was placed with quality controlled compaction every 15 cm. The subgrade layer had a high elastic modulus (178 MPa) due to the Neoloy Geocell reinforcement.

An additional layer of Neoloy Geocell 330-120 was installed in the base layer filled with base quality granular aggregate (+3 cm overfill). The 20 cm base layer also had a very high modulus, as a result of the Neoloy reinforcement. The platform surface layer was 25 cm Portland Concrete Cement slab.

 

 

  • Fast, simple installation 4 weeks to install 10,000 sq m of pavement
  • Modulus Improvement Factor – by 2-3x; enabled use of subgrade material
  • Subgrade improvement – 3D “mattress” stabilized extreme subgrade conditions
  • Confined drainage system – mission critical considering site conditions
  • Cost savings – reduced subgrade extraction, subbase and concrete layers